Strain, compound microbial inoculant and method for rapidly preparing luocheng za powder

Abstract

This invention discloses bacterial strains, compound microbial agents, and a method for rapidly preparing Luocheng rice noodles, relating to the field of food processing technology. The bacterial strains used for preparing Luocheng rice noodles include *Geotrichum candida* (…). Galactomyces candidum ) Mei3303.1, Pediococcus acidilactici ( Pediococcus acidilactici Mei.1103.1 and Lactobacillus paracasei ( Lactobacillus paracasei Both Mei1104.02 and Mei1104.02 have been deposited at the China General Microbiological Culture Collection Center. The beneficial effects of this invention are that by strengthening the fermentation process with compound microbial agents, it can improve fermentation efficiency, shorten fermentation time, inhibit the growth of other miscellaneous bacteria, and improve the flavor stability and safety of rice noodles.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of food processing, in particular to a strain for preparing Luocheng Zafen, a compound microbial inoculant and a method for rapidly preparing Luocheng Zafen BACKGROUND

[0002] The world's rice noodles look at China, and China's rice noodles look at Jiangxi. Jiangxi rice noodles have a thousand flavors and are still fresh after a long time. As a rice processing staple product that is deeply loved by people, it can be divided into fermented rice noodles and non-fermented rice noodles. Luocheng Zafen is a typical representative of Jiangxi fermented rice noodles and is a non-material cultural heritage of Jiangxi. It is famous for its unique flavor and has been broadcast on the screen of the "Chinese Food" program in 2021. Unlike the general rice noodle making process, Jiangxi Luocheng Zafen is made from late indica rice instead of early indica rice, and then naturally fermented for a long time (20-40 days) and processed. Long-term fermentation changes the composition of rice and produces many unique flavor substances, leaving a deep impression on people.

[0003] However, the natural fermentation process is long, the microbial community structure changes greatly, and it is easy to be infected with miscellaneous bacteria, making the flavor of Luocheng Zafen unstable and posing a safety hazard. In addition, the drying of Luocheng Zafen relies on sun drying, and the flavor precursor substances produced during the deep fermentation process need to be converted during the drying process to produce enough alkenal flavor substances. Alkenal substances are a class of compounds with special flavor characteristics, and their flavor threshold is lower than that of saturated aldehydes. They have an important contribution to the overall flavor in the fields of food, beverages, spices, etc. If the fermentation time is simply shortened or the drying is done by using electric heating drying technology, there will be quality problems such as broken strands, uneven strands, and insufficient flavor. The "weather-dependent" production mode of Luocheng Zafen has seriously hindered its market development.

[0004] To enhance the market competitiveness of traditional fermented rice noodles, while improving the production efficiency of Luocheng Zafen, the characteristic flavor and quality of Luocheng Zafen should be preserved to the maximum extent, just like Liuzhou Spicy Noodle attracts many consumers through flavor. Therefore, how to scientifically improve the production efficiency of Luocheng Zafen and maximize the preservation of the characteristic flavor and quality of Luocheng Zafen is a technical problem that needs to be solved. SUMMARY

[0005] The purpose of this invention is to at least solve one of the technical problems existing in the prior art, and to provide a strain, a compound microbial agent, and a method for rapidly preparing Luocheng rice noodles. This invention uses a compound microbial agent composed of native Luocheng rice noodle strains *Geotrichum candida*, *Pediococcus lactis*, and *Lactobacillus paracasei* to enhance the fermentation process. Drying is performed using a drying device equipped with infrared and ultraviolet lamps of specific wavelengths instead of sun-drying. This not only enriches the prepared Luocheng rice noodles with aldehydes and enols, but also increases the fermentation rate, ensuring the quality of the Luocheng rice noodles and preserving the unique flavor of traditional Luocheng rice noodles, thereby greatly increasing the market competitiveness of Luocheng rice noodles. Furthermore, it eliminates the dependence on weather for production. The prepared Luocheng rice noodles not only have a significantly shortened fermentation time, but also have a flavor composition most similar to traditional Luocheng rice noodles, rich in aldehydes and enols, and exhibit far less breakage and clumping than traditional Luocheng rice noodles. Therefore, the preparation method provided by this invention can rapidly produce flavorful and high-quality Luocheng rice noodles without relying on weather conditions, making it suitable for industrial production and greatly increasing the market competitiveness of Luocheng rice noodles.

[0006] The technical solution of the present invention is as follows:

[0007] A first aspect of the present invention provides a strain for preparing Luocheng rice flour, said strain comprising *Geotrichum candida* (…). Galactomyces candidum ) Mei3303.1, Pediococcus acidilactici ( Pediococcus acidilactici Mei.1103.1 and Lactobacillus paracasei ( Lactobacillus paracasei Mei1104.02;

[0008] The aforementioned *Geotrichum candida* Mei3303.1 is deposited at the China General Microbiological Culture Collection Center (CGMCC) on November 11, 2024, with accession number CGMCC NO.41622, and the deposit address is Institute of Microbiology, Chinese Academy of Sciences, No. 3, Courtyard 1, Beichen West Road, Chaoyang District, Beijing.

[0009] The *Pediococcus lactis* Mei.1103.1 is deposited at the China General Microbiological Culture Collection Center (CGMCC) on November 11, 2024, with accession number CGMCC NO.32564, and the deposit address is Institute of Microbiology, Chinese Academy of Sciences, No. 3, Courtyard 1, Beichen West Road, Chaoyang District, Beijing.

[0010] The Lactobacillus paracasei Mei1104.02 is deposited at the China General Microbiological Culture Collection Center (CGMCC) on November 11, 2024, with accession number CGMCC NO.32561. The deposit address is No. 3, Courtyard 1, Beichen West Road, Chaoyang District, Beijing, Institute of Microbiology, Chinese Academy of Sciences.

[0011] A second aspect of the present invention provides a compound microbial agent for preparing Luocheng rice flour, comprising the aforementioned *Geotrichum candida* Mei3303.1, *Pediococcus lactis* Mei.1103.1, *Lactobacillus paracasei* Mei1104.02, and excipients.

[0012] A third aspect of the present invention provides the application of the strain or the compound microbial agent described herein in the preparation of Luocheng Zhafen (a type of rice noodle).

[0013] A fourth aspect of the present invention provides a method for rapidly preparing Luocheng rice flour, comprising the following steps:

[0014] S1. Soak the washed and dried late-season indica rice in water, and inoculate it with the strain or the compound microbial agent to ferment it.

[0015] S2. After fermentation is complete, the fermented late-season indica rice is ground into a paste, filtered, formed into balls, steamed, extruded into powder, cooked, cooled, coiled, and dried to produce Luocheng rice noodles.

[0016] Preferably, the amounts of *Geotrichum candida* Mei3303.1, *Pediococcus lactis* Mei.1103.1, and *Lactobacillus paracasei* Mei1104.02 added are 10g each. 4 ~10 6 CFU / g, 10 5 ~10 7 CFU / g and 10 5 ~10 7 CFU / g.

[0017] Preferably, the method includes the following specific steps:

[0018] 1) Washing the rice: Rinse the late-season indica rice with water until clean;

[0019] 2) Soaking rice: Soak the washed late-season indica rice in water, with the amount of water being 1.2 to 1.5 times the dry weight of the rice;

[0020] 3) Fermentation: Add the strain or compound microbial agent mentioned above to the soaked rice and seal it for fermentation. The fermentation temperature is 25~35 ℃ and the fermentation time is 7~15 days.

[0021] 4) Grinding: After the late-season indica rice has fermented, it is ground into rice paste using a wet grinding method;

[0022] 5) Pressing and filtering: Press the wet-ground rice slurry with a plate and frame filter press to filter out the water and form rice noodle blocks, controlling the moisture content of the rice noodle blocks to be 38-45%;

[0023] 6) Forming dough: The filtered rice flour blocks are pressed into cylindrical dough balls with a bottom diameter of 10-14 cm and a height of 15-25 cm using a dough forming machine;

[0024] 7) Steaming the dough: Steam the prepared cylindrical dough at 100~105℃ for 60~80 minutes;

[0025] 8) Extrusion: The steamed dough is extruded into noodles with a diameter of 2.0~2.4 mm by applying pressure;

[0026] 9) Cooking the rice noodles: Heat the extruded rice noodles in boiling water for 4-6 minutes;

[0027] 10) Cooling: After cooking, remove the rice noodles and place them in cold water to cool.

[0028] 11) Coiling the rice noodles: Place the cooled rice noodles in a mold with dimensions of 25×15×5 cm and coil them into a row.

[0029] 12) Drying: Place the cooled vermicelli in a light drying device to dry, which is the Luocheng rice noodle.

[0030] Preferably, the light drying device includes:

[0031] Blower assembly, including a circulating blower for blowing air onto materials;

[0032] Conveying components, including mesh belt conveyors for conveying materials;

[0033] The material breaking up assembly includes a breaking up rod for turning over and breaking up the material being conveyed on the mesh belt conveyor, the breaking up rod being disposed above the mesh belt conveyor;

[0034] Heating components, including heaters for heating materials conveyed on mesh belt conveyors;

[0035] Illumination components, including infrared and ultraviolet lamps, are used to illuminate the materials conveyed on the mesh belt conveyor.

[0036] The controller is connected to the fan assembly, transmission assembly, agitation assembly, heating assembly, and lighting assembly respectively to control their operation;

[0037] The light drying device also has a material outlet and a material inlet, with the material outlet located above the transmission component and the material inlet located below the transmission component.

[0038] Preferably, the mesh belt conveyor includes a first mesh belt conveyor, a second mesh belt conveyor, and a third mesh belt conveyor arranged sequentially from top to bottom. The first mesh belt conveyor, the second mesh belt conveyor, and the third mesh belt conveyor are arranged horizontally and rotate clockwise, counterclockwise, and clockwise, respectively.

[0039] Preferably, the material-dispersing assembly further includes a first placement plate and a second placement plate, both of which are arc-shaped and respectively disposed above the first and second row mesh belt conveyors; a dispersing rod is disposed on the first and second placement plates, and the dispersing rod includes a drive motor, a rotating rod, and rotating beads. The drive motor drives the rotating rod to rotate, and the rotating beads are disposed on the rotating rod. The rotating beads are positioned facing the conveyor belts on the first and second row mesh belt conveyors and can adhere to the surface of the material.

[0040] The fifth aspect of the present invention provides Luocheng rice noodles, obtained by the method described above.

[0041] This invention has at least one of the following beneficial effects:

[0042] 1) This invention uses a compound microbial agent composed of native strains of Luocheng rice noodles to enhance the fermentation process, which can improve fermentation efficiency, shorten fermentation time, inhibit the growth of other miscellaneous bacteria, and improve the flavor stability and safety of rice noodles.

[0043] 2) This invention uses a self-made drying device instead of sun drying, which can produce Luocheng rice noodles with similar flavor and quality to traditional Luocheng rice noodles without relying on the weather, thus improving production efficiency.

[0044] 3) The preparation method provided by the present invention produces Luocheng rice noodles that are rich in enaldehyde flavor substances, giving them an appealing flavor that other rice noodles do not possess. Attached Figure Description

[0045] Figure 1 This is a schematic diagram of the overall structure of the drying device in the embodiment;

[0046] Figure 2 This is a schematic view of the drying device in the embodiment;

[0047] Figure 3 This is a schematic left view of the drying device in the embodiment;

[0048] Figure 4 This is a schematic diagram of the placement plate and the rubbing rod of the drying device in the embodiment;

[0049] Figure 5 This is a schematic diagram of the rubbing rod of the drying device in the embodiment;

[0050] Figure 6 These are micrographs of *Lactobacillus paracasei*, *Pediococcus lactis*, and *Geotrichum candida* in the examples.

[0051] Figure 7 The GC-MS spectra of Luocheng Zhafen in Comparative Example 1 and Example 3 are shown.

[0052] Figure 8The images are GC-MS spectra of Luocheng Zhafen in Comparative Examples 2 and 3.

[0053] Attached diagram labels: 1. Fan assembly; 2. Conveying assembly; 3. Dispersing assembly; 4. Heating assembly; 5. Illumination assembly; 6. Controller; 7. Material outlet; 8. Material inlet; 11. Circulating fan; 21. First row mesh belt conveyor; 22. Second row mesh belt conveyor; 23. Third row mesh belt conveyor; 31. First placement plate; 32. Second placement plate; 33. Dispersing rod; 331. Rotating ball; 332. Rotating rod; 333. Drive motor; 41. Heater; 51. Infrared lamp; 52. First ultraviolet lamp; 53. Second ultraviolet lamp. Detailed Implementation

[0054] To make the technical problems solved, the technical solutions, and the beneficial effects of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0055] Example 1: Strain Screening

[0056] I. Screening of Geotrichum candida

[0057] Initial screening: The fermentation broth of Luocheng rice noodles from the Luocheng Fermented Rice Noodle Factory in Yichun City, Jiangxi Province, was serially diluted and spread onto commercially available Bengal Red Agar. The mixture was then incubated at 28 ℃ for 48 h. At appropriate dilutions (30-300), single colonies of typical strains were picked and purified by streaking on three zones of the agar. The surface and microscopic morphology of individual colonies were observed. Strains matching the characteristics of the target genus were transferred to slant culture for preservation and ITS testing. Finally, *Geotrichum candida* (white ground mold) was identified. Galactomyces candidum 16 plants, numbered Mei3303.1-Mei3303.16.

[0058] Secondary screening: (1) Rice fermentation: Soak the washed and dried late-season indica rice in water, with the amount of water being 1.35 times the dry weight of the late-season indica rice. Then, inoculate 16 strains of Geotrichum candida into the rice, with an inoculation amount of 10. 5 CFU / g, control the fermentation temperature at 30 ℃, and seal for fermentation for 7 days. (2) Processing of Luocheng rice noodles: After the rice is fermented, it is ground, filtered, formed into balls, steamed, squeezed, cooked, cooled, rolled, and sun-dried to make Luocheng rice noodles. (3) Sensory evaluation: 10 people with sensitive senses, certain knowledge of rice noodles and able to accurately describe sensory feelings were selected to form an evaluation group to evaluate the flavor of 16 kinds of cooked Luocheng rice noodles. The results showed that the flavor of 8 kinds of Luocheng rice noodles was significantly richer than that of other Luocheng rice noodles, namely Mei3303.1-Mei3303.8.

[0059] II. Screening of Pediococcus lactis

[0060] Preliminary screening: *Pediococcus lactis* Mei.1103.1 was screened from fermented rice flour broth from Luocheng, Jiangxi Province. The specific method was as follows: an appropriate amount of fermented rice was placed in sterile nutrient broth and enriched at 37℃. Then, appropriate concentration gradients were selected and inoculated onto MRS solid medium. Strains with different colony morphologies, sizes, and colors were picked and streaked onto plates. This streaking process was repeated multiple times to obtain pure cultures of lactic acid bacteria. A total of 20 *Pediococcus lactis* strains were isolated, named Mei.1103.1-Mei.1103.20, and the isolated bacteria were preserved in glycerol stock tubes.

[0061] Secondary screening: (1) Rice fermentation: Soak the washed and dried late-season indica rice in water, with the amount of water being 1.35 times the dry weight of the late-season indica rice. Then, inoculate 20 strains of Pediococcus lactis into each strain, with an inoculation amount of 10. 6 CFU / g, control the fermentation temperature at 30 ℃, and seal for fermentation for 7 days. (2) Luocheng rice noodle processing: the preparation method is the same as that of white ground mold. (3) Sensory evaluation: 10 people with sensitive senses, certain knowledge of rice noodles and able to accurately describe sensory feelings were selected to form an evaluation group to evaluate the flavor of 20 kinds of cooked Luocheng rice noodles. The results showed that the flavor of 5 kinds of Luocheng rice noodles was significantly more intense than that of other Luocheng rice noodles, namely Mei.1103.1-Mei.1103.5.

[0062] III. Screening for Lactobacillus paracasei

[0063] Initial screening: The fermentation broth of Luocheng rice flour was serially diluted and spread onto MRS medium, and incubated at 37℃ for 48 h. At appropriate dilutions (30-300 cells / cell), single colonies of typical strains were picked and purified by streaking in three zones of the medium. The surface and microscopic morphology of individual colonies were observed. Strains matching the characteristics of the target genus were transferred to slant culture for preservation and 16S rDNA detection. Finally, 20 strains, including *Lactobacillus paracasei*, were identified, ranging from Mei 1104.01 to Mei 1104.20.

[0064] Secondary screening: (1) Rice fermentation: Soak the washed and dried late-season indica rice in water, with the amount of water being 1.35 times the dry weight of the late-season indica rice. Then, inoculate each rice with 20 strains of Lactobacillus paracasei, with an inoculation amount of 10. 6CFU / g, control the fermentation temperature at 30 ℃, and seal for fermentation for 11 days. (2) Luocheng rice noodle processing: the preparation method is the same as that of Gastrodia elata. (3) Sensory evaluation: 10 people with sensitive senses, certain knowledge of rice noodles and able to accurately describe sensory feelings were selected to form an evaluation group to evaluate the flavor of 20 kinds of cooked Luocheng rice noodles. The results showed that the flavor of 6 kinds of Luocheng rice noodles was significantly more intense than that of other Luocheng rice noodles, namely Lactobacillus paracasei of Mei1104.02 and Mei1104.04-Mei1104.08.

[0065] Example 2: Effects of three bacterial strains on volatile flavor compounds in Luocheng rice noodles

[0066] I. Effects of *Geotrichum candida* Mei3303.1-Mei3303.8 on volatile flavor compounds in Luocheng rice noodles

[0067] (1) Rice fermentation: Soak the washed and dried late-season indica rice in water, with the amount of water being 1.35 times the dry weight of the late-season indica rice. Then, inoculate the *Geotrichum candida* strains Mei3303.1-Mei3303.8 selected in Example 1, with an inoculation amount of 10 μg / L for each strain. 5 The concentration of CFU / g was controlled at a fermentation temperature of 30 °C, and the mixture was sealed and fermented for 11 days.

[0068] Meanwhile, under the same conditions, no bacterial strains were inoculated, and the mixture was fermented under natural conditions as a control group without inoculation.

[0069] (2) Processing of Luocheng rice noodles: After the rice is fermented, it is ground into a paste, filtered, formed into balls, steamed, squeezed, boiled, cooled, rolled, and dried in the sun to make Luocheng rice noodles.

[0070] (3) Detection of volatile flavor compounds: The content was determined by solid phase microextraction-gas chromatography-mass spectrometry (SPME-GC-MS) with a DB-Wax column (30 m × 0.25 mm × 0.25 μm, Agilent) and methyl myristate was used as an internal standard for relative quantification.

[0071] The test results are shown in Table 1.

[0072] Table 1

[0073]

[0074] As shown in Table 1, compared with other strains, strain Mei3303.1 had the highest content of volatile flavor compounds, and therefore was selected as the subsequent fermentation strain. Strain Mei3303.1 was identified as *Geotrichum candida* (…). Galactomyces candidum Its ITS sequence is shown in SEQ ID NO. 1, and the microscopic image of strain Mei3303.1 is shown in the image below. Figure 6 As shown.

[0075] II. Effects of *Pediococcus lactis* Mei.1103.1-Mei.1103.5 on volatile flavor compounds in Luocheng rice noodles

[0076] (1) Rice fermentation: Soak the washed and dried late-season indica rice in water, with the amount of water being 1.35 times the dry weight of the late-season indica rice. Then, inoculate the Pediococcus lactis strains Mei.1103.1-Mei.1103.5 selected in Example 1, with an inoculation amount of 10 μL for each strain. 6 The concentration of CFU / g was controlled at a fermentation temperature of 30 °C, and the mixture was sealed and fermented for 11 days.

[0077] The other steps are the same as for white ground mold.

[0078] The test results are shown in Table 2.

[0079] Table 2

[0080]

[0081] As shown in Table 2, compared with other strains, strain Mei.1103.1 had the highest content of volatile flavor compounds, and therefore was selected as the subsequent fermentation strain. Mei.1103.1 was identified as *Pediococcus lactis* (…). Pediococcus acidilactici The 16S rRNA sequence is shown in SEQ ID NO. 2, and the microscopic image of strain Mei.1103.1 is shown below. Figure 6 As shown.

[0082] III. Effects of Lactobacillus paracasei Mei1104.02, Mei1104.04-Mei1104.08 on volatile flavor compounds in Luocheng rice noodles

[0083] (1) Rice fermentation: Soak the washed and dried late-season indica rice in water, with the amount of water being 1.35 times the dry weight of the late-season indica rice. Then, inoculate the Lactobacillus paracasei Mei1104.02 and Mei1104.04-Mei1104.08 selected in Example 1, with an inoculation amount of 10. 6 The concentration of CFU / g was controlled at a fermentation temperature of 30 °C, and the mixture was sealed and fermented for 11 days.

[0084] The other steps are the same as for white ground mold.

[0085] The test results are shown in Table 3.

[0086] Table 3

[0087]

[0088] As shown in Table 3, compared with other strains, strain Mei1104.02 had the highest content of volatile flavor compounds, and therefore was selected as the subsequent fermentation strain. Mei1104.02 was identified as *Lactobacillus paracasei* (…).Lactobacillus paracasei The 16S rRNA sequence is shown in SEQ ID NO. 3, and the microscopic image of strain Mei1104.02 is shown below. Figure 6 As shown.

[0089] Example 3: Preparation of Luocheng Zhafen using a three-strain synergistic drying method combined with a light drying device.

[0090] A method for rapidly preparing Luocheng rice flour includes the following steps:

[0091] 1) Washing the rice: Rinse the late-season indica rice with water until clean;

[0092] 2) Soaking rice: Soak the washed late-season indica rice in water, with the amount of water being 1.35 times the dry weight of the rice;

[0093] 3) Fermentation: Add compound microbial agent to the soaked rice and seal it for fermentation. The fermentation temperature is 30 ℃ and the fermentation time is 11 days.

[0094] 4) Grinding: After the rice has fermented, it is ground into rice paste using a wet grinding method;

[0095] 5) Pressing and filtering: Press the wet-ground rice slurry into rice noodle blocks using a plate and frame filter press, controlling the moisture content of the rice noodle blocks to 41%;

[0096] 6) Forming dough: The filtered rice noodle blocks are pressed into cylindrical dough balls with a bottom diameter of 12 cm and a height of 20 cm using a dough forming machine;

[0097] 7) Steaming the dough: Steam the prepared cylindrical dough at 103 ℃ for 70 min;

[0098] 8) Extrusion: The steamed dough is extruded into noodles with a diameter of 2.2 mm by applying pressure;

[0099] 9) Cooking the rice noodles: Heat the extruded rice noodles in boiling water for 5 minutes;

[0100] 10) Cooling: After cooking, remove the rice noodles and place them in cold water to cool.

[0101] 11) Coiling the rice noodles: Place the cooled rice noodles in a mold with dimensions of 25×15×5 cm and coil them into a row.

[0102] 12) Drying: Place the cooled vermicelli in a light drying device to dry until the moisture content of the vermicelli is 12%, which is the Luocheng rice noodle;

[0103] 13) Sealed packaging.

[0104] Step 3) The bacterial strains in the compound microbial agent are: *Lactobacillus paracasei* Mei1104.02, *Pediococcus lactis* Mei.1103.1, and *Geotrichum candida* Mei3303.1, with *Lactobacillus paracasei* Mei1104.02 added at a concentration of 10... 6 The CFU / g concentration of *Pediococcus lactis* Mei.1103.1 was 10. 6 The amount of CFU / g added to *Geotrichum candida* Mei3303.1 was 10. 5 CFU / g.

[0105] The structure of the light drying device in step 12) is as follows: Figures 1-5 As shown, the light drying device includes a fan assembly 1, a transmission assembly 2, a rubbing assembly 3, a heating assembly 4, a lighting assembly 5, and a controller 6. The heating assembly 4 is located at the bottom of the light drying device, the fan assembly 1 is located at the top, and the transmission assembly 2, the rubbing assembly 3, and the lighting assembly 5 are located in the middle. The controller 6 is connected to the fan assembly 1, the transmission assembly 2, the rubbing assembly 3, the heating assembly 4, and the lighting assembly 5, and is used to control the opening, closing, and operating intensity of these components. In this embodiment, the controller 6 is located at the top of the light drying device. Since the structure and principle of the controller are well known to those skilled in the art, they will not be described in detail in this embodiment.

[0106] Specifically, the fan assembly 1 includes a circulating fan 11, which is located on top of the light drying device and connected to the controller 6, for blowing and drying the Luocheng rice powder on the transmission assembly 2.

[0107] The transmission component 2 includes a first row of mesh belt conveyors 21, a second row of mesh belt conveyors 22, and a third row of mesh belt conveyors 23 arranged sequentially from top to bottom. These conveyors are horizontally arranged and specifically include conveyor belts, motors, and other components. The motor drives the conveyor belts, thereby transporting the Luocheng rice flour placed on them. In this embodiment, the first row of mesh belt conveyors 21, the second row of mesh belt conveyors 22, and the third row of mesh belt conveyors 23 rotate clockwise, counterclockwise, and clockwise respectively, causing the Luocheng rice flour to circulate and be heated. This allows for a continuous supply of new, undried Luocheng rice flour, improving drying efficiency.

[0108] The light drying device is also equipped with a material outlet 7 and a material inlet 8, such as Figure 1 As shown, the material inlet 8 is located at the upper part of the lamp drying device, and the material outlet 7 is located at the lower part of the lamp drying device; as Figure 2As shown, the material inlet 8 is located above the first row of mesh belt conveyors 21. Specifically, an inclined feed plate is provided at the material inlet 8 so that the Luocheng rice powder entering from the material inlet 8 can fall onto the first row of mesh belt conveyors 21. The material outlet 7 is located below the third row of mesh belt conveyors 23. Specifically, an inclined discharge plate is provided at the material outlet 7 so that the Luocheng rice powder conveyed from the third row of mesh belt conveyors 23 can fall onto the discharge plate and be discharged through the material outlet 7.

[0109] The dispersing assembly 3 includes a first placement plate 31, a second placement plate 32, and a plurality of dispersing rods 33. The inner walls of the first placement plate 31 and the second placement plate 32 are arc-shaped and are respectively located diagonally above the first row of mesh belt conveyors 21 and the second row of mesh belt conveyors 22, that is, diagonally above the conveyor belts. Specifically, the inner walls of the first placement plate 31 and the second placement plate 32 are concave arc-shaped and are used to install the dispersing rods 33, so that the dispersing rods 33 can contact the Luocheng rice powder conveyed on the first row of mesh belt conveyors 21 and the second row of mesh belt conveyors 22.

[0110] The rubbing rod 33 is installed on the first placement plate 31 and the second placement plate 32. The rubbing rod 33 is specifically composed of a drive motor 333, a rotating rod 332, and rotating beads 331. The rotating beads 331 are set towards the conveyor belts on the first row of mesh belt conveyors 21 and the second row of mesh belt conveyors 22, so that they can adhere to the surface of Luocheng rice noodles and have a certain fixing effect on Luocheng rice noodles. This allows the Luocheng rice noodles to be turned over smoothly along the arc-shaped first placement plate 31 and the second placement plate 32, so that they are dried evenly. At the same time, the drive motor 333 drives the rotating rod 332 to rotate, so that the rotation direction of the rotating beads 331 is opposite to the conveying direction of Luocheng rice noodles, so that the Luocheng rice noodles are spread out in one direction and prevent them from clumping together.

[0111] The heating component 4 includes a heater 41 for heating the Luocheng rice flour on the first row of mesh belt conveyors 21, the second row of mesh belt conveyors 22, and the third row of mesh belt conveyors 23.

[0112] The illumination component 5 includes an infrared lamp 51, a first ultraviolet lamp 52, and a second ultraviolet lamp 53, such as... Figure 3 As shown, infrared lamp 51 is positioned on top of the first row of mesh belt conveyors 21, while first ultraviolet lamp 52 and second ultraviolet lamp 53 are positioned on the side walls of the light-drying device, specifically near the side walls of the first row of mesh belt conveyors 21, the second row of mesh belt conveyors 22, and the third row of mesh belt conveyors 23. Specifically, the infrared wavelength of the infrared lamp is 2-25 μm, and its radiant heat energy can quickly penetrate deep into the Luocheng rice flour to dry the moisture; the ultraviolet wavelength of the first ultraviolet lamp 52 and the second ultraviolet lamp 53 is 280-400 nm, which helps promote the conversion of flavor precursor substances.

[0113] The controller 6 is connected to the fan assembly 1, the transmission assembly 2, the rubbing assembly 3, the heating assembly 4, and the light assembly 5. By controlling the intensity of other components, it controls the drying rate of Luocheng rice flour, thereby ensuring that Luocheng rice flour is fully dried.

[0114] Therefore, the Luocheng rice flour is circulated and moved by the transmission component 2, and the rotating Luocheng rice flour is broken up by the rubbing component 3 to prevent it from sticking together. The Luocheng rice flour is dried evenly by the light component, the heating component, and the fan component. This ensures that the flavor precursor substances produced during the deep fermentation process can be fully converted to form Luocheng rice flour rich in aldehyde flavor substances.

[0115] In actual use, all switches in controller 6 are turned on. After preheating, the wet powder of Luocheng rice flour is placed into the drying device through the material inlet 8. It is conveyed by the first row of mesh belt conveyors 21 to the rubbing rods 33 on the first placement plate 31. After being rubbed and broken by the rotating beads 331, it slides along the arc surface of the first placement plate 31 and is turned over. Then, it is conveyed by the second row of mesh belt conveyors 22 to the rubbing rods 33 on the second placement plate 32, where it is rubbed and turned over again, and then conveyed by the third row of mesh belt conveyors 23 to the material outlet 7. After a long period of conveying and turning, Luocheng rice flour is quickly, evenly and thoroughly dried under the action of infrared lamp 51, first ultraviolet lamp 52, second ultraviolet lamp 53, heater 41, and circulating fan 11, and is rich in aldehyde flavor substances and has good quality characteristics.

[0116] Comparative Example 1: A method for preparing Luocheng rice flour through long-term natural fermentation

[0117] The difference from Example 3 is as follows: Step 3) fermentation is changed to: the soaked rice is fermented in an open environment at a temperature of 30°C for 30 days; Step 12) drying is changed to: the cooled rice noodles are placed in the sun to dry until the moisture content of the rice noodles is 12%, which is the Luocheng rice noodles. Other steps are the same as in Example 3.

[0118] Comparative Example 2: No inoculation with compound microbial agent + drying with light drying device

[0119] The difference from Example 3 is that step 3) fermentation is changed to: the soaked rice is sealed and fermented at a temperature of 30°C for 11 days. Other steps are the same as in Example 3.

[0120] Comparative Example 3: Three strains of bacteria were used in synergistic treatment combined with oven drying.

[0121] The difference from Example 3 is that step 12) drying is changed to: placing the cooled vermicelli in a 40 ℃ oven to dry until the vermicelli moisture content is 12%, which is the Luocheng rice noodle;

[0122] The other steps are the same as in Example 3.

[0123] Example 1: Determination of volatile flavor compounds

[0124] Determination method: Solid phase microextraction-gas chromatography-mass spectrometry (SPME-GC-MS) was used. The chromatographic column was DB-Wax (30 m × 0.25 mm × 0.25 μm, Agilent). Relative quantification was performed using peak area.

[0125] Based on the GC-MS spectra of Luocheng Zhafen from Comparative Examples 1-3 and Example 3 ( Figures 7-8 Analysis revealed the classification and content of volatile flavor compounds in Luocheng rice noodles, as shown in Table 4. In Comparative Examples 1-3 and Example 3, aldehydes accounted for over 70% of the total volatile compounds, indicating that aldehydes are the main volatile compounds in Luocheng rice noodles. Notably, Comparative Example 1, produced using traditional methods (natural fermentation and sun drying), exhibited a high content of alkenyl aldehyde flavor compounds (5467.62 μg / kg), demonstrating that alkenyl aldehyde flavor compounds are the primary characteristic flavor compounds of Luocheng rice noodles.

[0126] The content of enaldehyde-like flavor compounds in Luocheng rice flour from Example 3 was the highest among Examples 3 and Comparative Examples 2-3, and even higher than Comparative Example 1 by 1816.39 μg / kg. This indicates that, according to the preparation method provided by this invention, i.e., after modification with compound microbial agents and light-drying device, Luocheng rice flour rich in enaldehyde-like flavor compounds can be produced with a 63% reduction in fermentation time and without weather dependence. Comparative Example 2, which did not involve the addition of compound microbial agents during fermentation, had very few enaldehyde-like flavor compounds, with a content of only 65.42 μg / kg. This indicates that only by producing sufficient flavor precursors through fermentation with compound microbial agents can more enaldehyde-like flavor compounds be produced by the drying device described in this invention. Comparative Example 3, which produced sufficient flavor precursors through fermentation with compound microbial agents but was dried in an oven, had an enaldehyde-like flavor content that was 3203.00 μg / kg less than Comparative Example 1 and 5019.39 μg / kg less than Example 3, respectively. This indicates that only the light-drying device described in this invention can efficiently convert flavor precursors into enaldehyde-like flavor compounds.

[0127] In terms of the types of compounds, Comparative Example 1 detected 24 volatile compounds, while Examples 3 and Comparative Examples 2-3 detected 26, 11, and 13 volatile compounds, respectively. Furthermore, Examples 3 and Comparative Examples 2-3 contained the same number of compounds as Comparative Example 1 (22, 11, and 13, respectively). These results indicate that the flavor composition of Example 1 is closest to traditional Luocheng rice noodles, and it contains a wider variety of flavor compounds. Comparative Example 1 contained 10 enaldehyde flavor compounds, while Examples 3 and Comparative Examples 2-3 contained the same number of enaldehyde flavor compounds as Comparative Example 1 (10, 2, and 3, respectively), indicating that the characteristic flavor of Example 1 is closest to traditional Luocheng rice noodles.

[0128] In summary, according to the preparation method provided by this invention, after improvement with compound microbial agents and light drying device, Luocheng rice noodles with flavor composition most similar to traditional Luocheng rice noodles and rich in aldehyde flavor substances can be prepared in a short time and without relying on the weather.

[0129] Table 4: Classification and Content of Volatile Flavor Compounds in Luocheng Rice Noodles (Comparative Examples and Implementation Examples)

[0130]

[0131] Note: / indicates that it was not detected.

[0132] Example 2: Determination of natural breakage rate and sliver curling phenomenon

[0133] The steps for detecting the natural breakage rate are as follows: Open the packaging of Luocheng rice noodles, weigh the total mass M of Luocheng rice noodles, and then weigh the total mass m of the broken strips (strips less than 10 cm) that have fallen off the packaging. The natural breakage rate is expressed as m / M×100%.

[0134] Evaluation of the "cohesion" phenomenon: A panel of 10 individuals with sensitive senses, some knowledge of rice noodles, and the ability to accurately describe sensory experiences were selected. Cohesion refers to the phenomenon where two or more rice noodles stick together, forming a relatively thick strip. The evaluation panel assessed the cohesion phenomenon of Luocheng rice noodles based on the quantity and length of the strands. A 10-point scoring system was used, with 10 indicating no cohesion and 0 indicating complete cohesion. The average result was taken.

[0135] Table 5: Natural breakage rate and strip-binding phenomenon scores of Luocheng rice noodles in comparative and example samples

[0136]

[0137] Table 5 shows the natural breakage rate and bridging score of Luocheng rice noodles in the comparative examples and embodiments. Comparative Example 1 had a natural breakage rate of 13.8% and a bridging score of 5.2. Example 3, prepared after modification with compound microbial agents and a drying device, had a breakage rate of 5.6% and a bridging score of 8.6%, significantly better than traditional Luocheng rice noodles (Comparative Example 1), indicating that the preparation method provided by this invention can significantly improve the quality of Luocheng rice noodles. Comparative Example 2, without compound microbial agent fermentation, had the highest breakage rate and severe bridging, indicating that compound microbial agent fermentation significantly improves the quality of Luocheng rice noodles. Comparative Example 3, fermented with compound microbial agents but dried in an oven, had the lowest bridging score, indicating that the light drying device provided by this invention can effectively improve the bridging phenomenon.

[0138] In summary, the preparation method provided by this invention, after being improved with compound microbial agents and light drying equipment, can produce Luocheng rice flour of superior quality to that prepared by traditional methods without relying on weather conditions.

[0139] Summary of effects of comparative examples and implementation examples

[0140] A comprehensive comparison of volatile flavor, breakage rate, and bridging phenomenon revealed that, without weather dependence, the Luocheng rice noodle prepared according to the method provided by this invention not only significantly shortens the fermentation time but also exhibits a flavor composition most similar to traditional Luocheng rice noodle, rich in enaldehyde flavor compounds. Furthermore, the preparation method provided by this invention can reduce the occurrence of breakage and bridging in Luocheng rice noodle, thereby improving its quality.

[0141] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A strain for preparing roxazyme powder, characterized in that, The strains include Geotrichum candida ( Galactomyces candidum ) Mei3303.1, Pediococcus acidilactici ( Pediococcus acidilactici Mei.1103.1 and Lactobacillus paracasei ( Lactobacillus paracasei Mei1104.02; The white mold Mei3303.1 is preserved in the China General Microbiological Culture Collection Center, the preservation date is November 11, 2024, the preservation number is CGMCC NO.41622, and the preservation address is No.3, Yikuangli, Beichen West Road, Chaoyang District, Beijing, Institute of Microbiology, Chinese Academy of Sciences; The Pediococcus acidilactici Mei.1103.1 is preserved in the China General Microbiological Culture Collection Center, the preservation date is November 11, 2024, the preservation number is CGMCC NO.32564, and the preservation address is No.3, Yikuangli, Beichen West Road, Chaoyang District, Beijing, Institute of Microbiology, Chinese Academy of Sciences; The Lactobacillus paracasei Mei1104.02 is preserved in the China General Microbiological Culture Collection Center, the preservation date is November 11, 2024, the preservation number is CGMCC NO.32561, and the preservation address is No.3, Yikuangli, Beichen West Road, Chaoyang District, Beijing, Institute of Microbiology, Chinese Academy of Sciences.

2. A complex microbial agent for preparing Luozhaza powder, characterized in that, The white mold Mei3303.1, the Pediococcus acidilactici Mei.1103.1, the Lactobacillus paracasei Mei1104.02 and the auxiliary materials according to claim 1.

3. The use of the strain according to claim 1 or the complex microbial agent according to claim 2 in the preparation of Luocheng Zafen.

4. A method for rapidly preparing a roxithromycin powder, characterized in that, The method comprises the following steps: S1, soaking the washed and dried long-grain indica rice with water, and inoculating the strain according to claim 1 or the complex microbial agent according to claim 2 for fermentation; S2, after the fermentation is completed, the fermented long-grain indica rice is ground into pulp, filtered, formed into a pellet, steamed, extruded into noodles, cooked, cooled, spread, and dried to prepare Luocheng Zafen.

5. The method of claim 4, wherein, The added amount of the white geotrichum Mei3303.1, lactate diploococcus Mei.1103.1, and paracasein lactobacillus Mei1104.02 is respectively 10 4 ~10 6 CFU / g, 10 5 ~10 7 CFU / g, and 10 5 ~10 7 CFU / g.

6. The method of claim 4, wherein, The method comprises the following specific steps: 1) washing rice: washing the long-grain indica rice with water; 2) soaking rice: soaking the washed long-grain indica rice with water, and the water soaking amount is 1.2-1.5 times the dry weight of the long-grain indica rice; 3) fermentation: adding the strain according to claim 1 or the complex microbial agent according to claim 2 to the soaked rice for sealed fermentation, the fermentation temperature is 25-35 ℃, and the fermentation time is 7-15 days; 4) grinding: after the long-grain indica rice fermentation is completed, the rice is ground into pulp by wet grinding; 5) filter pressing: the wet ground rice pulp is pressed and filtered into rice powder blocks by a plate and frame filter press, and the water content of the rice powder blocks is controlled to be 38-45%; 6) pelletizing: the filter-pressed rice powder blocks are extruded into cylindrical pellets with a bottom diameter of 10-14 cm and a height of 15-25 cm by a pelletizing machine; 7) steaming: the prepared cylindrical pellets are steamed with 100-105 ℃ steam for 60-80 min; 8) noodle extrusion: the steamed pellets are extruded into noodles with a diameter of 2.0-2.4 mm by pressure; 9) noodle cooking: the extruded noodles are heated in boiling water for 4-6 min; 10) cooling: the cooked noodles are taken out and cooled in cold water; 11) Disc powder: the cooled noodle is placed in a mold with a length, width and height of 25x15x5 cm to form a row of powder; 12) Drying: the cooled noodle is placed in a light drying device for drying, which is the Luocheng Za powder.

7. The method of claim 6, wherein, The light drying device comprises: A fan assembly (1) comprising a circulating fan (11) for blowing the material; A conveying assembly (2) comprising a mesh belt conveyor for conveying the material; A rubbing assembly (3) comprising a rubbing rod (33) for turning over and rubbing the material conveyed on the mesh belt conveyor, the rubbing rod (33) being arranged above the mesh belt conveyor; A heating assembly (4) comprising a heater (41) for heating the material conveyed on the mesh belt conveyor; An illumination assembly (5) comprising infrared and ultraviolet lamps for illuminating the material conveyed on the mesh belt conveyor; A controller (6) connected to the fan assembly (1), the conveying assembly (2), the rubbing assembly (3), the heating assembly (4) and the illumination assembly (5) for controlling their operation; The light drying device also has a material outlet (7) and a material inlet (8), the material outlet (7) being arranged above the conveying assembly (2), and the material inlet (8) being arranged below the conveying assembly (2).

8. The method of claim 7, wherein, The mesh belt conveyor comprises a first mesh belt conveyor (21), a second mesh belt conveyor (22) and a third mesh belt conveyor (23) arranged in sequence from top to bottom, the first mesh belt conveyor (21), the second mesh belt conveyor (22) and the third mesh belt conveyor (23) being arranged in the horizontal direction and rotating in clockwise, counterclockwise and clockwise directions, respectively.

9. The method of claim 8, wherein, The rubbing assembly (3) further comprises a first placement plate (31) and a second placement plate (32), the first placement plate (31) and the second placement plate (32) being arc-shaped and arranged obliquely above the first mesh belt conveyor (21) and the second mesh belt conveyor (22), respectively; the rubbing rod (33) is arranged on the first placement plate (31) and the second placement plate (32), the rubbing rod (33) comprising a driving motor (333), a rotating rod (332) and a rotating ball (331), the driving motor (333) driving the rotating rod (332) to rotate, the rotating ball (331) being arranged on the rotating rod (332), the rotating ball (331) being arranged towards the conveying belt on the first mesh belt conveyor (21) and the second mesh belt conveyor (22) and being able to adhere to the surface of the material.

Images